1. Field of the Invention
This invention relates to a hand-operated wrench, and more particularly to a compact three-in-one combination wrench with great accessibility to fasteners and workpieces. A preferred embodiment in accordance with this invention includes a ratchet wrench in the center of the wrench body, an open-end V-shaped socket wrench at one end of the wrench body, and an adjustable mortise-tenon pivotal wrench at the other end. The two handle portions in between the above-mentioned three parts are ergonomically adapted for a friendly human-machine interface.
2. Description of Prior Art
It is the goal of this invention to provide some feasible solutions for problems encountered in the prior art, as stated below.
FIG. 7 depicts a T-handle wrench with a sleeve or a socket configured at the end of the bar, which is perpendicular to the handle. Wrenches of this kind are only applicable to certain sizes of fasteners that fit into the one-size sleeve, and hence have limited applications.
FIG. 8 shows an improvement on T-type wrenches, which is configured to have a ratchet wrench at the head of the wrench body, and a drive shaft for engaging sleeves of various sizes. This kind of wrenches, however, requires a working space of at least the diameter of the length of the wrench body for a 360-degree rotation about fasteners, not desirable for operation in cramp spaces.
In a basic socket wrench embodiment, the main body is made cylindrical in shape, as shown by handle 32′ of a conventional wrench (3′) in FIG. 9, which is also configured with drive shaft 31′ to accommodate a wide range of workpieces. In U.S. Pat. No. 6,792,833 to Macor a double-ended wrench having a flat elongated-shaped handle is produced to overcome the inconvenience of gripping a bulky cylindrical handle. In the present invention, a symmetrical streamlined dual-handle is designed to relieve muscular stiffness in holding substantially straight handles.
U.S. Pat. No. 6,862,956 to Chen, as well as U.S. Pat. No. 6,807,882 to Hu disclose ratchet wrenches with a simplified structure, both of which still have the disadvantage of complexity in assembly, demanding higher precision in machining.